Physical principles of defibrillators

Defibrillators use a capacitor to store a preset quantity of electrical charge and then rapidly deliver it as direct current to the myocardium to treat cardiac arrhythmias. They also incorporate an inductor to prolong the duration of the delivered current, and a rectifier to convert alternating current (AC) to direct current (DC).Modern defibrillators may be automated, and produce biphasic waveforms which increase safety and efficacy. Miniature implantable cardioverter-defibrillators (ICD) may be used in patients with recurrent life-threatening arrhythmias.